Consciousness and Cognition
September 1, 2017
Renate Rutiku, Talis Bachmann
Electroencephalographic (EEG) potentials remain a valuable source of data and theories about the neural correlates of consciousness (NCC). This review organizes published work on EEG-based markers of NCC according to the time course of brain potentials relative to stimuli for which awareness is measured or manipulated. Brain potentials are treated as both dependent and independent variables. A notable pattern across studies is that relative negativization of event-related potentials (ERPs) tends to mark NCC.
Consciousness and Cognition
March 1, 2017
Frederick Travis, Niyazi Parim, Amrita Shrivastava
Listening to live Vedic recitation produces deeper inner experiences and distinct brain patterns compared to Transcendental Meditation (TM) practice. Thirty-seven subjects reported that Vedic recitation felt deeper, more internal, and characterized by lively silence. EEG recordings showed significantly higher theta2 and alpha1 coherence in frontal, parietal, and frontal-parietal regions during Vedic recitation than during TM. Theta2 coherence, associated with attending to internal mental processes, supports subjects' descriptions of the recitations as internal vibrations rather than external sounds. Higher alpha1 coherence, seen during pure consciousness experiences in TM, supports reports of greater depth during recitation.
Consciousness and Cognition
February 1, 2017
Jana Speth, Astrid M Schloerscheidt, Clemens Speth
Mental time travel to the future is reduced during REM and non-REM sleep compared to waking. Three independent judges analyzed 563 mentation reports from sleep onset, REM sleep, non-REM sleep, and waking using a validated linguistic tool based on grammatical and cognitive-semantic theories. The data indicate that both REM and non-REM sleep are characterized by a reduction in future-oriented mental time travel, supporting earlier physiological evidence at the level of brain function.
Consciousness and Cognition
February 1, 2017
Judith Katz, Noam Saadon-Grosman, Shahar Arzy
A life-review experience (LRE) involves vividly seeing a succession of one's own life events. Although common in near-death experiences, its occurrence in the general population is not well understood. In-depth qualitative interviews with 7 people who had a full LRE identified several subtypes of characteristics, including order, continuity, covered period, extension to the future, valence, emotions, and perspective taking. A questionnaire developed from these features was administered to 264 participants of diverse ages and backgrounds, and the resulting LRE-score showed a normal distribution. The findings indicate that LRE has well-defined characteristics and that its subcomponents may also appear in healthy people, suggesting a cognitive continuum of life-event representation that may become more pronounced under extreme stress.
Consciousness and Cognition
November 1, 2016
Michael Dambrun
A reduction in the salience of perceived body boundaries leads to increased happiness and decreased anxiety. Participants who practiced a body scan meditation reported greater happiness and less anxiety than those in a control condition, and the change in happiness was mediated by the change in perceived body boundaries, suggesting that selflessness elicits happiness through the dissolution of perceived body boundaries.
Consciousness and Cognition
November 1, 2016
Petr Bob, Matthew Laker
Stressful experiences can cause physiological disturbances and neuroanatomical changes, while psychotherapy and meditation may influence brain functions. Traumatic stress often involves a dissociative response that disintegrates conscious experience. Self-reflection is essential for posttraumatic growth, which is linked to spiritual experiences and meditation states that enable mental integration and create a novel integrated self. There is no widely accepted evidence about specific neural mechanisms of mental integration related to spiritual experiences and meditation, but growing evidence shows these integrative experiences relate to alterations in brain physiology and morphology. These findings offer a new paradigm for understanding mental disorders and emphasize the fundamental role of mental integration and an integrated self in psychiatric therapy.
Consciousness and Cognition
November 1, 2016
Laura Aymerich-Franch, Damien Petit, Gowrishankar Ganesh et al.
Synchronized multisensory cues can make healthy people feel as though their self is located outside their body, resembling an out-of-body experience. This study tested whether healthy individuals can also feel a sense of self in two bodies at once. Using a humanoid robot embodiment system, participants received audio-visual feedback and controlled the robot's head movements and walking. When they observed themselves through the embodied robot, they reported an illusion strongly resembling heautoscopy—the experience of seeing one's own body from a second body. The results suggest that a healthy human mind can bi-locate, perceiving self-location and self-identification in two different bodies simultaneously.
Consciousness and Cognition
October 1, 2016
Jana Speth, Astrid M Schloerscheidt, Clemens Speth
Mental time travel to the future, but not to the past, decreases during sleep onset hypnagogia. Three independent judges analyzed 150 mentation reports collected before and after sleep onset, using a linguistic tool grounded in grammatical and cognitive-semantic theories. The results indicate that memory for the future diminishes at sleep onset, supporting preliminary physiological evidence at the level of brain function. This state of consciousness may help dissociate between mental time travel to the past and the future, despite recent research emphasizing similarities in their cognitive and physiological processes.
Consciousness and Cognition
May 1, 2016
R. Costa, J. Pestaña, D. Costa et al.
Altered states of consciousness involving changes in the sense of self, time, and space are linked to sexual responsiveness. In a study of 116 subjects, greater body awareness and lesser awareness of time and space were associated with higher satisfaction, desire, arousal, and orgasm occurrence. For women, satisfaction, desire, and arousal were especially tied to reduced time awareness. Female orgasms during vaginal intercourse were related to greater body awareness and less time awareness, but orgasms from noncoital activities showed no such link. The findings suggest that attentional absorption during sex enhances sexual responsiveness, particularly in women, and to a lesser degree in men.
Consciousness and Cognition
May 1, 2016
Denholm J Aspy
Retrospective questionnaires asking people how often they remember dreams produce lower recall rates than daily logbooks, a gap called the retrospective-logbook disparity. One explanation is that retrospective measures underestimate true dream recall; another is that keeping a logbook boosts recall. This study tested both possibilities using several retrospective and logbook measures across three logbook types. The disparity correlated with variables tied to retrospective underestimation and was larger among participants who reported improved recall during the logbook period. The findings suggest that retrospective measures underestimate dream recall and that keeping a logbook enhances it. Recommendations for using each measurement method are offered.
Consciousness and Cognition
May 1, 2016
Shan-Chuan Teng, Yunn-Wen Lien
A month-long, 12-hour movement-based contemplative practice called Body-Mind Axial Awareness (BMAA), rooted in Confucian traditions, improved working memory capacity more than Chan-meditation or a waiting-list control. Chan-meditation, but not BMAA, improved attentional switching compared to the control group. No differences were found for inhibition. The findings suggest that movement-based and mindfulness-based practices may enhance different aspects of executive functions in distinct ways.
Consciousness and Cognition
April 1, 2016
Tracey L. Kahan, Stephanie Claudatos
Dreams are dominated by vision, audition, and movement rather than smell, touch, or taste, and include both positive and negative emotions along with various cognitive processes. Ratings of 788 dreams from 144 college women using the Subjective Experiences Rating Scale identified ten subscales: four sensory, three affective, one cognitive, and two structural (events/actions, locations). Process-oriented features (sensory, cognitive, affective) were more strongly correlated with each other than with content-centered structural features. Cognition and positive emotion were linked to more phenomenal features than negative emotion, a pattern also seen in waking autobiographical memory.
Consciousness and Cognition
April 1, 2016
Clemens Speth, Jana Speth
As people fall asleep, reflective thinking declines while motor imagery increases, indicating a shift toward interacting with an imaginary, hallucinatory world. In 150 mentation reports from 16 participants awakened at different times after sleep onset, cognitive and motor agency analysis—objective linguistic tools—showed a decrease in the reflective thinking needed to recognize the hallucinatory quality of the state, alongside an increase in motor imagery. These spontaneous changes in consciousness map onto physiological states, potentially aiding future exploration of conditions where consciousness declines and possibilities for treatment.
Consciousness and Cognition
December 1, 2015
Aline Gauchat, Jean R Séguin, Esther McSween-Cadieux et al.
Recurrent dreams in young adolescents aged 11–15 years most often involve confrontations with monsters or animals, physical aggression, falling, and being chased. Analysis of 102 dream reports shows these dreams contain more negative than positive content. Only half include threatening elements, providing mixed support for the threat simulation theory of dreaming. Differences between adolescent and adult recurrent dreams are discussed, along with possible sex effects.
Consciousness and Cognition
September 1, 2015
Christian Ebner, Henning Schroll, Gesche Winther et al.
A neuro-computational model explains how the brain gates information into consciousness, specifically in the distractor-induced blindness task. In this task, participants view rapid streams of colored dots and report intervals of coherent motion preceded by a target color. When distractors (motion intervals before the target color) appear, detection of the target motion declines, especially when the delay between target color and target motion is short. The model proposes that conscious perception requires reverberating activity in cortico-subcortical loops, with basal ganglia pathways either allowing or inhibiting this reverberation. Distractors trigger suppression via the inhibitory hyperdirect pathway, and when a target follows closely, lingering suppression prevents its identification. The model reproduces experimental data on how delay length affects detection probability.
Consciousness and Cognition
July 1, 2015
Vanessa Charland-Verville, Zulay Lugo, Jean-Pierre Jourdan et al.
Memories of near-death experiences (NDEs) are usually emotionally positive, but this study compared NDEs in 8 patients with locked-in syndrome (LIS) from acute brainstem lesions to 23 classical NDE experiencers after coma with supratentorial lesions. LIS NDEs less frequently included feelings of peacefulness or well-being. The findings suggest that NDEs with less positive emotions may stem from impaired pontine/paralimbic connectivity or from the emotional distress of being conscious while paralyzed.
Consciousness and Cognition
May 1, 2015
Denholm J Aspy, Paul Delfabbro, Michael Proeve
Two methods are commonly used to measure dream recall at home: retrospective questionnaires (a single question asking people to estimate their recall) and daily logbooks. Retrospective measures tend to yield lower dream recall rates than logbooks. One explanation is that retrospective measures underestimate actual dream recall; another is that keeping a logbook enhances recall. If both effects occur, neither method reflects typical dream recall rates, and each may be confounded with variables linked to underestimation or enhancement. This review addresses the insufficient attention this issue has received.
Consciousness and Cognition
May 1, 2015
Christina Merrick, Melika Farnia, Tiffany K Jantz et al.
The stream of consciousness, often seen as free and whimsical, is actually more open to external influence than previously thought. An experimental manipulation successfully triggered not just one but two involuntary thoughts in participants: they were asked to avoid subvocalizing the names of visual objects and to avoid counting the number of letters in those object names. On many trials, participants experienced both types of involuntary thoughts, which arose from distinct high-level processes (naming and counting). This is the first demonstration of inducing two involuntary thoughts into the stream of consciousness, with stimulus word length systematically affecting the results. The findings have implications for attention, imagery, and action control.
Consciousness and Cognition
November 1, 2014
Georg Northoff
William James described consciousness as a 'stream' with 'substantive parts' (the contents of consciousness) and 'transitive parts' (the linkages between contents). While much research has focused on substantive parts, the neural basis of transitive parts and how they balance 'sensible continuity' and 'continuous change' in inner time consciousness remains unclear. This paper develops a neuro-phenomenal hypothesis proposing that cortical midline structures, with their high variability and strong low-frequency fluctuations, mediate this phenomenal balance.
Consciousness and Cognition
October 3, 2014
S. Wilkinson
Auditory verbal hallucinations (AVHs) can be explained by a predictive processing framework that views them as arising from abnormalities in how the brain predicts sensory input. This approach accounts for both the auditory phenomenology of AVHs and their variety, including three distinct subtypes. The predictive processing framework addresses two challenges facing popular self-monitoring theories: explaining why AVHs are experienced as auditory events and why they take different forms.
Consciousness and Cognition
October 1, 2014
Kelly Bulkeley
A digital word search method using 40 categories built into the Sleep and Dream Database website can accurately identify distinctive patterns in dream content. Applied to four classic dream sets—the male and female Norm dreams from Hall and Van de Castle, the Engine Man dreams from Hobson, and the Barb Sanders Baseline 250 dreams from Domhoff—the approach replicated findings from previous labor-intensive analyses. The results demonstrate that word search technologies are compatible with traditional methods of dream content analysis, offering greater accuracy, objectivity, and speed.
Consciousness and Cognition
April 1, 2014
Pilleriin Sikka, Katja Valli, Tiina Virta et al.
Emotional experiences in dreams may appear inconsistent across studies because of whether dream emotions are self-rated or judged by external raters. In a sleep-laboratory study, 17 participants were awakened from REM sleep and provided oral dream reports, then rated their own emotions using a modified scale. External judges rated the same reports with the same scale. Self-ratings yielded higher estimates of emotional dreams, positively valenced dreams, the number of positive and negative emotions per dream, and various discrete emotions compared to external ratings. The discrepancy appears largely due to underrepresentation of positive emotions in dream reports when judged externally.
Consciousness and Cognition
September 1, 2013
Jana Speth, Clemens Frenzel, Ursula Voss
Dream reports collected after REM sleep describe more physical movement by the dreamer, while hypnagogic hallucinations (the imagery experienced just before falling asleep) are mostly experienced passively, as an observer. The findings come from linguistic analysis of reports given immediately after EEG-monitored periods of hypnagogia and REM sleep in a sleep laboratory. The method, called Activity Analysis, quantifies the level of simulated motor activity in subjective reports. This approach could be used to study altered activity levels in conditions such as depression or PTSD.
Consciousness and Cognition
September 1, 2013
Armando D'Agostino, Giacomo Aletti, Martina Carboni et al.
In acutely psychotic patients with a single fixed delusion, fragments of that delusional thought appear in their dreams, suggesting continuity between waking delusions and dream content. Ten patients reported dreams during an acute psychotic break. Sixteen judges, with varying familiarity with each patient's delusion, tried to group the dreams by matching them to the correct patient. Most judges performed only slightly above chance, and no significant differences emerged between groups with different levels of acquaintance. Scoring dreams for specific delusional themes revealed continuity for Grandiosity and Religion. The findings indicate that some delusional contents recur within patients' dreams, possibly reflecting ongoing memory consolidation processes relevant to delusion formation.
Consciousness and Cognition
March 1, 2013
Laura Mirams, Ellen Poliakoff, Richard J Brown et al.
A brief body-scan mindfulness meditation training reduced the misperception of touch and increased tactile sensitivity in healthy participants, compared with a control group that listened to a recorded story. Sixty-two participants completed a somatic signal detection task before and after the intervention. The meditation group reported fewer false perceptions of near-threshold vibrations that were not actually present. This suggests that the nature of interoceptive attention matters for perceptual accuracy, and body-scan meditation might help reduce misperception of physical symptoms in people with medically unexplained symptoms.